Newsgroups: comp.sys.transputer
From: davidb@ndl.co.uk (David Boreham)
Subject: Re: inmos IMS 2620P-12 IC's, what are these?
Organization: Network Designers Limited
Date: Tue, 15 Mar 1994 11:04:50 GMT
Message-ID: <CMpDG3.89y@ndl.co.uk>

In article <2m1eb7$ejk@thor.cs.utexas.edu>, cpg@cs.utexas.edu (Carlos M. Puchol) says:
>
>Let me first apologize if this is not the appropriate group to post
>this quick query, but some of you may know about this.
>
>I have a bunch of integrated circuits from an old (I guess) transputer
>board for a PC. These chips have the following on top of them:
>
>inmos 8506-B
>IMS 2620P-12
>
>Can someone tell me (through email preferably) what kind of chips are
>these? I would guess they are memories, but they may not be.

Its a 64K DRAM, 16K by 4. 120ns access time.

The other number is the date code, indicating that the device was tested
and marked in the sixth week of 1985.

For those interested in trivia, the numbering scheme works like this:

The first digit signifies the device type. "1" is SRAM, "2" is DRAM, 3 is "EEPROM"
The second digit is the number of bits, as in 2 to the power of the (digit +10)
The third digit is the word width, as 2 to the power of the digit.
The last digit is for function variations, as in Nibble mode etc.

(Is that right Paul ?)

I can't even remember which boards had these in, must have been a B001 or
something totally old. Perhaps the first B004s had these in ?
If you need to replace these devices, look for other manufacturers devices,
probably numbered "4416" or something like that. These parts are long
obsolete though. Your best bet for a datasheet is to get hold of an old memory
databook for any DRAM manufacturer cira 1985/6 and look for the 16K by 4s,
they call used the same pinout.




